The present invention relates to a switch which interconnects an electrical card and a printed circuit board, and particularly to a switch for detecting full insertion of an electrical card in a housing mounted on a printed circuit board.
A conventional electrical connector is disclosed in U.S. Pat. No. 6,130,387. In this patent, an electrical connector has a built-in switch assembly for detecting a smart card (not shown) that has reached a fully inserted position in the connector. The switch assembly includes an insulative support for mounting on a circuit board, and a switch contact with a pedal extending above an upper face of the support. The switch contact is downwardly deflected by a card as the card reaches its fully inserted position. The switch contact has a connecting tab permanently engaged to a first switch trace on the circuit board, and a contact suspended over a second switch trace on the circuit board. When the pedal is depressed, the contacting part is actuated to press against the second trace and thereby close the switch.
Unfortunately, because the pedal extends above the upper face of the support, the pedal tends to push the card upwardly. This results in an unreliable connection between the card and the connector. Furthermore, the card must be pushed with enough force to close the switch. The card therefore tends to yield or become damaged after repeated use, often resulting in erroneous reading or writing of the card.
Hence, an improved electrical card connector is needed to overcome the above-mentioned deficiencies of current electrical card connectors.
Accordingly, a primary object of the present invention is to provide an electrical connector having a card detecting switch which prevents mis-connection between a card and the connector.
Another object of the present invention is to provide an electrical connector having a card detecting switch which avoids distortion of cards received in the connector.
An electrical connector for connecting an electrical card with a printed circuit board (PCB) has a housing receiving signal contacts therein, a switch for detecting full insertion of the card, and a guide frame slidably engaged with the housing. The switch includes a fixed contact and a resilient contact, which are in contact with each other when the switch is in a normal position. The fixed contact has a contact piece connected to a first switch trace of the PCB. The resilient contact has a solder tab connected to a second switch trace of the PCB, and a spring arm opposite the solder tab for contacting the contact piece. The guide frame has a wedge for disengaging the spring arm from the contact piece when the card is fully inserted into the housing.
In use, the guide frame with the card supported therein is slid toward the housing. When the card reaches its fully inserted position, the wedge is interposed between the contact piece of the fixed contact and the spring arm of the resilient contact, thereby breaking the connection therebetween and opening the switch.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.